Major depression and stages of smoking. A longitudinal investigation.
BACKGROUND
Epidemiologic studies have reported an association between major depression and smoking. This prospective study examines the role of depression in smoking progression and cessation, and the role of smoking in first-onset major depression.


METHODS
Data are from a 5-year longitudinal epidemiologic study of 1007 young adults. Incidence and odds ratios (ORs) are based on the prospective data. Hazards ratios are based on the combined lifetime data and estimated in Cox proportional hazards models with time-dependent covariates.


RESULTS
Based on the prospective data, history of major depression at baseline increased significantly the risk for progression to daily smoking (OR, 3.0; 95% confidence interval, 1.1-8.2), but did not decrease significantly smokers' rate of quitting (OR, 0.8; 95% confidence interval, 0.4-1.6). History of daily smoking at baseline increased significantly the risk for major depression (OR, 1.9; 95% confidence interval, 1.1-3.4). These estimates were reduced somewhat when history of early (ie, before age 15 years) conduct problems was controlled. Estimates based on lifetime data were consistent with these results.


CONCLUSIONS
The observed influences from major depression to subsequent daily smoking and smoking to major depression support the plausibility of shared etiologies. Separate causal mechanisms in each direction might also operate, including self-medication of depressed mood as a factor in smoking progression and neuropharmacologic effects of nicotine and other smoke substances on neurotransmitter systems linked to depression.
Breslau
N
N
Department of Psychiatry, Henry Ford Health Sciences Center, Detroit, Mich., USA. nbresla1@hfhs.org
Peterson
E L
EL
Schultz
L R
LR
Chilcoat
H D
HD
Andreski
P
P
D000328:Adult; D000367:Age Factors; D015897:Comorbidity; D003866:Depressive Disorder / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D008824:Michigan / Q000453:epidemiology; D011446:Prospective Studies; D012044:Regression Analysis; D012307:Risk Factors; D012494:Sampling Studies; D012651:Self Medication / Q000523:psychology; D012907:Smoking / Q000453:epidemiology* / Q000523:psychology; D016540:Smoking Cessation